[Bloat] incremental deployment, transport and L4S (Re: when does the CoDel part of fq_codel help in the real world?)

[Mikael Abrahamsson]

On Thu, 29 Nov 2018, Sebastian Moeller wrote:

> 	As far as I can tell intel is pushing atom/x86 cores into its 
> docsis SoCs (puma5/6/7) as well as into the high-end dsl SoCs (formerly 
> lantiq, 
> https://www.intel.com/content/www/us/en/smart-home/anywan-grx750-home-gateway-brief.html?wapkw=grx750), 
> I am quite confident that those also pack enough punch for CPU based 
> routing at Gbps-rates. In docsis modems these are already rolled-out, I 
> do not know of any DSL modem/router that uses the GRX750

"10 Gbit/s packet processor".

Game over, again.

> Call me naive, but the solution to the impasse at getting a common 
> definition of diffserv agreed upon is replacing all TCP CC algorithms? 
> This is replacing changing all endpoints (and network nodes) to honor 
> diffserve with changing all endpoints to use a different TCP CC. At 
> least I would call that ambitious.... (unless L4S offers noticeable 
> advantages for all participating without being terribly unfair to the 
> non-participating legacy TCP users*).

L4S proposes a separate queue for the L4S compatible traffic, and some 
kind of fair split between L4S and non-L4S traffic. I guess it's kind of 
along the lines of my earlier proposals about having some kind of fair 
split with 3 queues for PHB LE, BE and the rest. It makes it deployable in 
current HW without the worst kind of DDoS downsides imaginable.

The Internet is all about making things incrementally deployable. It's 
very frustrating, but that's the way it is. Whatever we want to propose 
needs to work so-so with what's already out there and it's ok if it takes 
a while before it makes everything better.

I'd like diffserv to work better, but it would take a lot of work in the 
operator community to bring it out to where it needs to be. It's not 
hopeless though, and I think 
https://tools.ietf.org/html/draft-ietf-tsvwg-le-phb-06 is one step in the 
right direction. Just the fact that we might have two queues instead of 
one in the simplest implementations might help. The first step is to get 
ISPs to not bleach diffserv but at least allow 000xxx.

-- 
Mikael Abrahamsson    email: swmike at swm.pp.se